Abstract

The coherent control of optical images has garnered attention because all information embedded in optical images is expected to be controlled in a parallel way. One of the most important control processes is switch for information delivery. We experimentally demonstrated phase-controlled optical image switching in a double-Λ system where the transmission of the image through a medium was switched. Two independent laser sources were adopted for a double-Λ system such that images inscribed in two weak probe light beams were incoherent with each other. Arbitrary phase was added to the optical images to show that switching could be accomplished just with the relative phase difference between the probe pixels.

The probe transmission with a magnetic field at the condition of two relative phase differences between probe fields in a double-Λ system. A two-photon detuning in a doubleΛ system was occurred by a scanned magnetic field applied to Rb atoms. The conversion scale from magnetic field to frequency detuning is 1.4 MHz/G. The measured FWHM linewith of double EIT was 358 KHz.

All-optically switched images and the phase shifts of the probe fields with two cases ((a) and (c)). (a) Phase shift distributions of each probe field induced by SLM. Gray levels corresponds to phase shift induced by SLM. (b) Transmitted image (left) of (a) phase shift and a contrast-inverted image by the PZT-induced π phase over all pixels of one probe field (right). (c) Phase distributions of each probe field induced by SLM. The relative phase shift between two probe fields was H shaped π (a phase box size 40×48 μm2). (d) Transmitted image (left) of (c) phase shift and a contrast-inverted image with π-phase shifted by PZT (right).